on behalf of someone
idiom
variants:
or on someone's behalf
Definition of on behalf of someone
1
: as a representative of someone
The teacher accepted the award on behalf of the whole class.
2
or US in behalf of someone
or in someone's behalf
: for the benefit of someone : in support of someone
She spoke in behalf of the other candidate. They're willing to do anything on their child's behalf.
3
: because of someone
Don't get up on my behalf.